So sánh x

- Hướng dẫn giải

Ta có:

$y-\left(\frac{4}{15}+\frac{1}{5}\right):\frac{4}{9}=\frac{5}{8}$

$y-\frac{7}{15}:\frac{4}{9}=\frac{5}{8}$

 $y-\frac{7}{15}x\frac{9}{4}=\frac{5}{8}$

$$\begin{gathered} \mathrm{y}-\frac{21}{20}=\frac{5}{8} \\ \mathrm{y}=\frac{5}{8}+\frac{21}{20} \\ \mathrm{y}=\frac{67}{40} \end{gathered}$$

Ta lại có 

$\left(x+\frac{5}{6}\right)x\frac{12}{25}=\frac{47}{50}$

$x+\frac{5}{6}=\frac{47}{50}:\frac{12}{25}$

 $x+\frac{5}{6}=\frac{47}{50}x\frac{25}{12}$

$$\begin{gathered} x+\frac{5}{6}=\frac{47}{24} \\ x=\frac{47}{24}-\frac{5}{6} \\ x=\frac{9}{8} \end{gathered}$$

Vì $\frac{9}{8}<\frac{67}{40}$ nên x < y.

Vậy y > x hay x < y

Đáp án cần chọn là B